Mozart and Schubert both died in their 30s. The former left his Great Mass in C minor incomplete, and the latter’s Symphony No. 8 remained unfinished at their respective deaths. Yet the elegance and lyrical beauty of both have captivated audiences ever since. Grand Rapids Symphony Chorus joins the orchestra for the Mass in C minor, which Mozart composed with his wife, Constanze, in mind as the soprano soloist, hoping that his new bride’s performance would impress his father, Leopold Mozart. Regarding The Unanswered Question by the Yankee iconoclast Charles Ives, Aaron Copland, the dean of American composers, declared it to be “among the finest works ever created by an American artist.” 8 p.m. Friday and Saturday, Nov. 16-17, in DeVos Performance Hall, 303 Monroe Ave. NW. Tickets start at $18 adults, $5 students.